How soon do you mobilize an injured muscle? If mobilization of the muscle occurs immediately after the injury, it has been shown that excessive connective scar tissue will form, and re-rupture of the area will occur more easily.1 It was found that placing a rat's injured muscle to rest using a cast for a few days after the injury prevented excessive scar formation and re-rupture at the injury site.
Jarvinen, et al.,2 discuss the validity of the RICE principle (rest, ice, compression, and elevation) recommended for most soft-tissue injuries. While there has not been any randomized clinical trial to prove the value of RICE for soft-tissue injury,4 there is some evidence for each of the individual factors. Evidence supporting the principle of rest for a few days is discussed previously. Regarding the use of ice, Bleakley, et al.,4 concluded that many more high-quality trials are needed to provide evidence-based guidelines for using ice in the treatment of acute soft-tissue injuries. In examining the literature, there was marginal evidence that ice plus exercise is most effective after ankle sprain and post-surgery. There was little evidence to suggest that the addition of ice to compression had any significant effect, but this was restricted to treatment of hospital inpatient cases. Few studies assessed the effectiveness of ice on closed soft-tissue injury, and there was no evidence of an optimal mode or duration of treatment. Clinically, early use of ice has been associated with smaller hematomas between the ruptured myofiber stumps and less inflammation; it also helps speed up early regeneration.5 Compression reduces the intramuscular blood flow to the injured areas, but applying it immediately after injury has not been proven to actually accelerate the healing of the injured skeletal muscle.2,6 Jarvinen2 recommends that "the combination of ice and compression be applied in shifts of 15 to 20 minutes in duration, repeated at intervals of 30 to 60 minutes," since this procedure has resulted in a 50 percent reduction in intramuscular blood flow. Physiologically, elevation above heart level should help decrease hydrostatic pressure and thereby reduce the accumulation of interstitial fluid.
The formation of scar tissue is necessary for the healing of muscle, and the great majority of skeletal muscle injuries heal without the formation of the functionally disabling fibrous scar. Increased fibroblastic proliferation could become excessive and create dense scar tissue, but this occurs mostly with a major muscle trauma or with re-ruptures. At times, the scar can even restrict the regeneration of the myofibers across the injury gap.2
Normal healing of a muscle injury consists of regeneration of muscle fibers and formation of a connective tissue scar. The healing also is greatly dependent on the ingrowths of vascularity and regeneration of intramuscular nerve branches.7 The gap between the ruptured muscle is filled with a hematoma, which the body hopefully will rid itself of by phagocytosis. An early extracellular matrix (ECM) is formed from the blood-derived fibrin and fibronectin, which act as a scaffold for the fibroblasts. The fibroblasts synthesize more of the tissue that makes up the new ECM, so the muscle tissue can withstand any contraction forces initially applied to the area. It is no longer thought that general fibrosis occurs in the healing skeletal muscle unless the muscle is completely immobilized for a substantial period of time.2 At first, the new connective tissue scar is the weakest point of the injured skeletal muscle, but after about 10 days, the new cross-linked scar becomes stronger than the adjacent normal muscle tissue. In the early stages of the injury, the ends of the ruptured muscle are aided in their attachment to the new scar by the regenerating myofibers, which adhere to the ECM on its lateral aspects. This reduces the pull on the early fragile scar, helping to prevent early re-rupture, before the healing is completed. From a manual treatment point of view, "mechanical stress is a prerequisite for the lateral adhesion, as recent experimental studies have shown that the phenomenon does not occur in the absence of mechanical stress."2
- Jarvinen M. Healing of a crush injury in rat striated muscle, 2: a histological study of the effect of early mobilization and immobilization on the repair processes. Acta Pathol Microbiol Scand 1975;83A:85-94.
- Jarvinen TA, Jarvinen TLN, Kaariainen M, et al. Muscle injuries, biology and treatment. Amer J Sports Med 2005;33(5):745-764.
- Jarvinen TA, Kaariainen M, Jarvinen M, Kalimo H. Muscle strain injuries. Curr Opin Rheumatol, March 2000;12(2):155-61. Review.
- Bleakley C, McDonough S, Macauley D. The use of ice in the treatment of acute soft tissue injury: a systematic review of randomized controlled trials. Am J Sports Med 2004;33:251-261.
- Deal DN, Tipton J, Rosencrance E, et al. Ice reduces edema: a study of microvascular permeability in rats. J Bone Joint Surg Am 2002;84:1573-1578.
- Thorsson O, Lilja B, Nilsson P, Westin N. Immediate external compression in the management of an acute muscle injury. Scand J Med Sci Sports 1997;7:182-190.
- Lehto MU, Jarvinen MJ. Muscle injuries, their healing process and treatment. Ann Chir Gynaecol 1991;80(2):102-8.
- Kaariainen M, Liljamo T, Pelto-Huikko M, et al. Regulation of 7-integrin by mechanical stress during skeletal muscle regeneration. Neuromuscul Disord 2001;11:360-369.
Warren Hammer, MS, DC, DABCO
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